Grinding machine



June 10, 1952 o, 2,599,992

GRINDING MACHINE Filed May 2, 1951 3 Sheets-Sheet l ffl 'ftor O/VA E. HILL I June 10, 1952 o. E. HILL 2,599,992

GRINDING MACHINE Filed May 2, 1951 s Sheets-Sheet 2 20b O/vA E. HILL flscorney June 10, 1952 H L 2,599,992

GRINDING MACHINE ret t d-Jase 10, 1 952 UNITED STATES PATENT OFFICE GRINDING MACHINE Oiva E. Hill, West Boylston, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application May 2, 1951, Serial No. 224,189

. 8 Claims. 1

The invention relates to" grinding machines and more particularly to-an automatically controlled mechanismto compensate for taper on a workpiece.

One object of the invention is to provide a simple and thoroughly practical grinding machine with an automatically controlled mechanism for compensating for taper on a workpiece. Another object of the invention is 'to provide a grinding machine 'with an automatically controlled mechanism for moving the swivel table to compensate for differences of diameter in two spaced portions of a workpiece. Another object of the invention is to provide an automatically controlled mechanism for swivelling the work table so that two or more spaced grinding wheels may grind portions of a workpiece to the desired and predetermined size. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, and arrangements of parts, as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a plan view of a grinding machine embodying this invention;

Fig. 2 is a combined hydraulic and electrical diagram illustrating the hydraulic and electrical controls for the machine;

Fig. 3 is a fragmentary cross-sectional view. on an enlarged scale, through the grinding machine showing the grinding wheel feeding mechanism;

Fig. 4 is a fragmentary cross-sectional view, on an enlarged scale, taken approximately on the line 4--4 of Fig. 1 through the table swivelling mechanism;

Fig. 5 is a fragmentary vertical sectional view. on an enlarged scale, taken approximately on the line 5-5 of Fig. 1 through the nut for controlling the swivelling movement of the table;

Fig. 6 is a fragmentary sectional view through a work gauging head; and

Fig. 7 is a. fragmentary view showing a modification illustrating the application of this invention to a wide wheel grinding operation.

A grinding machine has been illustrated in the drawings comprising a base III which supports a longitudinally reciprocable table II on a flatway l2 and a V-way l3 formed on the upper surface of the base Ill. The table H serves as a support for a swivel table |4- which is mounted to pivot about a stud l5 fixedly supported on the table I.

The swivel table l4 serves as a support for a rotatable work supporting mechanism comprising a headstock 20 which is driven by an electric motor 2|. The headstock 20 is provided with a headstock center 22 for supporting the left-hand end of a workpiece 23 to be ground. The swivel table I4 also supports a footstock 24 having a footstock center 25 for rotatably supporting the right-hand end of the workpiece 23.

The base l0 also serves as a support for a transverselymovable wheel slide 30 which is arranged to slide transversely on a suitable V and flatway (not shown) formed on the upper surface of the base Ill. The wheel slide 30 is provided with a rotatable wheel spindle 3| which supports a plurality of spaced grinding wheels 32, 33, 34 and 35 which are arranged to grind spaced portions 36, 31, 38 and 39 of the workpiece 23. The wheel spindle 3| may be driven by means of an electric motor 4|] mounted on the upper surface of the wheel slide 30. The motor is provided with an armature shaft 4| which supports a multiple V-groove pulley 42. The pulley 42 is connected by multiple V-belts 43 with a multiple V-groove pulley 44 mounted on the right-hand end of the wheel spindle 3|.

A suitable wheel feeding mechanism may be provided for producing a transverse feeding movement of the wheel slide 30. This mechanism may comprise a rotatable feed screw 45, the left-hand end of which is slidably keyed within a rotatable sleeve 46. The right-hand end of the feed screw 45 is journalled in antifriction bearings 41 carried by a sleeve 48 which is journalled in a cylindrical aperture 49 formed within the base Hi. The wheel slide 30 is provided with a depending half-nut 50 which meshes withthefeed screw 45.

The sleeve 46 is rotatably journalled in an anti-friction bearing 5| carried by the base I0. A shaft 52 is slidably keyed within the left-hand end of the sleeve 46. The other end of the shaft 52 is provided with a gear 53 which meshes with a gear 54. The gear 54 is mounted on a rotatable shaft 55. The lefthand end of the shaft 55 is provided with a gear 56 which meshes with a gear 51. The gear'5l is rotatably supported on a shaft '58 and is adjustablyconnected with a manually operable feed wheel 59 by meansof a micrometer adjusting mechanism 60. It will be readily apparent from. the foregoing disclosure that a rotation motion of the feed wheel 59 will be imparted through the mechanism above described to rotate the feed screw 45 and thereby produce a transverse feeding movement of the wheel slide 39 together with the grinding wheels 32, 33, 34 and 35. The direction of rotation of the feed wheel 59 determines the direction of movement of the slide 39.

A wheel positioning and feeding mechanism is provided for causing the wheel slide 39 to move forwardly to an operative position by means of an hydraulically operated mechanism comprising a cylinder 65. The cylinder 65 contains a slidmounted piston 56 which is connected to one end of a piston rod 51. The piston rod 51 is arranged in axial alignment with the feed screw 45 and the slidably mounted sleeve 48. The lefthand end of the piston rod G'I is fastened to the sleeve 48.

A feed control valve '19 is provided for controlling the admission to and exhaust of fluid from the cylinder 65. This valve is a piston-type valve comprising a. valve stem 'II having a plurality of spaced valve pistons I2, I3 and It formed integrally therewith. The valve pistons I2, I3 and I4 are spaced from each other to form valve chambers I5 and I5. A compression spring I? serves normally to hold the valve stem II in a right-hand end position. An electric solenoid 83 when energized serves to shift the valve stem toward the left to reverse the flow of fluid to the cylinder 65.

A suitable hydraulic system is provided for supplying fluid under pressure to the cylinder 55. This system may comprise a motor driven fluid pump 80 which draws fluid through a pipe 8i from a fluid reservoir 92 and forces fluid under pressure through a pipe 93 to the control valve III. A pressure relief valve 35 is provided in the pipe line 83 by means of which excess fluid under pressure may be returned directly through a pipe 85 into the reservoir 82. In the position of the valve III (Fig. 2) fluid under pressure in the pipe 83 passes through the valve chamber I5, through a passage 89 into a cylinder chamber 81 to cause the piston 69 to move toward the right into the position illustrated in Fig. 2. During this movement of the piston 65 fluid within a cylinder chamber 88 exhausts through a passage 89, through the valve chamber I5 and through an exhaust pipe 99 into the reservoir 82.

Fluid under pressure passing through the passage 86 may pass through a port 9I into the cylinder chamber 8'! or during the initial movement thereof may pass through a ball check valve 92, through a passage 93, through a port 94 into the cylinder chamber 81.

It is desirable to provide a suitable cushioning means for slowing down the rapid approaching movement of the wheel slide 36 before the piston 66 engages the left-hand end of the cylinder 55. This is preferably accomplished by arranging the port 9I so that the piston 65 covers the port 9! before the piston 69 engages the left-hand end of the cylinder 65. After the port 9| is covered, fluid under pressure exhausts through the port 94 through the passage-93, through a throttle valve 95 into the passage 89. It will be readily apparent from the foregoing disclosure that the throttle valve 95 serves to slow down the exhaust of fluid from the cylinder chamber 8! thereby cushioning the movement of the piston 56 as it moves into a left-hand end position.

Similarly it may be desirable to cushion the rearward movement of the wheel slide 39. This ably is preferably accomplished by a dashpot mcha nism comprising a dashpot piston 91 which is slidably mounted with a dashpot cylinder 98. Before the piston 56 reaches the right-hand end of the cylinder 55, a projection 99 on the piston rod 5? engages the dashpot piston 91 so that fluid exhausting from the dashpot cylinder 98 must pass through a pipe or passage I90, through a throttle valve IiiI into the passage 89. The setting of the throttle valve IilI determines the cushioning movement of the dashpot piston 91. A ball check valve I92 is provided so that when fluid under pressure is passed through the passage 89 into the cylinder chamber 88, fluid under pressure may also pass through the ball check valve I92 to refill the dashpot cylinder chamber for the next cushioning movement.

A suitable feeding mechanism is provided for producing a slow precise feeding movement of the grinding wheels during the grinding operation. In the preferred form, a hydraulically operated mechanism is provided so that the feed screw 45 may be rotated to produce the desired grinding feed. As above described, a manually operable feed wheel 59 is mounted on the front of the machine base I9. The feed wheel 59 is operatively connected to rotate the gear 51' which meshes with the gear 56 keyed on the front end of the shaft 55. A hydraulically operated mechanism is provided comprising a cylinder I95 which contains a slidably mounted piston I06. The upper surface of the-piston I96 is provided with a rack bar I91 which meshes with a gear I09. The gear H39 is fixedly mounted on a rotatable shaft I99. The shaft I99 also carries a gear III) which meshes with the gear 59. It will be readily apparent from the foregoing disclosure that when fluid under pressure is admitted to either end of the cylinder I95 to cause an endwise movement of the piston I06, a rotary motion will be imparted, through the mechanism above described, to rotate the feed screw 45 and thereby impart a feeding movement to the wheel slide 99 and the grinding wheels 92, 39, 39 and 95.

A suitable bypass valve I04 is provided to facilitate manual rotation of the feed wheel 59 when desired. This valve is preferably a piston type valve having a plurality of spaced valve pistons III, H2 and H3. When it is desired to manually adjust the feed wheel 59, a valve H4 in the pipe line 83 may be opened to pass fluid through a pipe H5 into an end chamber H6 of the bypass valve I94. Pressure in the chamber I16 causes the valve member to move toward the right (Fig. 2) so that fluid may readily bypass from a chamber I93 at the left-hand end of the cylinder I95, through a passage II'I, through a valve chamber H8 formed in the bypass valve I94, through a passage I I9 into a cylinder chamber I29 at the right-hand end of the cylinder I05 so that the feed wheel 59 may be readily rotated manually.

The feed control valve I0 is preferably arranged to control the admission to and exhaust of fluid under pressure to the cylinder I65. As illustrated in Fig. 2 fluid under pressure passed through the pipe 83 into the valvechamber I5 may pass through a pipe I25, through a ball check valve I29 and through a pipe or passage I21, through a valve chamber I28 formedbetween the valve pistons H2 and H3 and through the passage II9 into the chamber I29 to reset the piston I96 when the piston 55 and the wheel slide 30 are moved to a rearward or inoperative position after a grinding operation.

When the solenoid S3 is energized to initiate an infeeding movement of the grinding wheel, fluid under pressure from the pipe 83 enters the valve chamber 15 and passes through the passage 89 into the cylinder chamber 88 to cause the piston 66 and the grinding wheel slide 30 to move forward at a rapid rate. At the same time fluid under pressure entering the valve chamber 16 passes through a pipe I30, through th valve chamber H8 in the bypass valve I04, through the passage II1 into the cylinder chamber II6 to cause the piston I06 to move toward the right to initiate a slow rotation of the feed screw 45 at a grinding speed. During this movement of the piston I86 toward the right, fluid within the cylinder chamber I20 exhausts through the passage II9, through the valve chamber I28 in the bypass valve I04, through the pipe I21 and through a throttle valve I29 into the pipe I25 where the fluid exhausts through the control valve into the reservoir 82. The setting of the throttle valve I29 determines the rate of movement of the piston I06 toward the right and thereby determines the rate of rotation of the feed screw 45 and the rate of infeeding movement of the wheel slide 30 and the grinding wheels 32, 33, 34 and 45.

In order to attain the main object of this invention, it is desirable to provide an automatically actuated swivel mechanism automatically to swivel the swivel table I4 so as to compensate for taper on a workpiece or to compensate for differences in diameter of spaced portions on a workpiece. This mechanism may comprise a rotatable screw I35 which is journalled in bearings I36 and I31 in the table II. The screw I35 meshes with a nut I38. The nut I38 is arranged to slide transversely in an elongated slot I39 formed in the upper surface of the table II. The nut I38 is provided with an upwardly extending boss I40 which mates with an aperture formed in a slide block MI. The slide block MI is arranged to slide longitudinally in an elongated slot I42 formed in the underside of the swivel table I4. The elongated slot I42 and the elongated slot I39 serve to facilitate an endwise movement of the nut I38 during a swivel adjustment.

A hydraulically operated mechanism is provided for imparting a rotary motion to the screw I38. This mechanism may comprise a fluid pressure cylinder I45 which contains a slidably mounted piston I46. The piston I46 is provided on its upper surface with a rack bar I41 which meshes with a gear I48 keyed on the left-hand end of the swivel screw I35. When fluid under pressure is passed through a pipe I49 into a cylinder chamber I50, the piston I46 will be caused to move toward the right (Fig. 2) to cause a rotation of the swivel screw I35 so as to swivel the swivel table I4 in a counterclockwise direction (Fig. 2). During this movement fluid within a cylinder chamber I5I may exhaust through a pipe I52. Similarly if fluid under pressure is passed through the pipe I52 into the cylinder chamber I5I, the piston I46 will be caused to move toward the left thereby imparting a rotary motion to the swivel screw I35 to cause a clockwise adjustment of the swivel table I4 (Fig. 2). A control valve I55 is provided for controlling the admission to and exhaust of fluid through the pipe I49. This valve is a piston type valve comprising a valve stem I56 having a plurality of spaced pistons formed integrally therewith forming a plurality of valve chambers I51, I58 and I59. A compression spring I60 serves normally to maintain the valve stem I56 in a left-hand end position so that no fluid may pass from the pressure pipe 83 into the pipe I49. In this position of the valve I55, fluid may exhaust from the pipe I49 into the valve chamber I59, through a central aperture I6I formed within the valve stem I56, into the-valve chamber I51 and out through a pipe I62, through a throttle valve I63 and a pipe I64 into the reservoir. The throttle valve I63 serves to determine the rate of exhaust of fluid from the cylinder chamber I50. A solenoid SI is provided which when energized serves to shift the valve stem I56 toward the right so that fluid under pressure in the pipe 83 passes into the valve chamber I58 and through the pipe I49 into the valve chamber I50 to move the piston I46 toward the right. A similar valve I65 is provided for controlling the admission to and exhaust of fluid through the pipe I52. The valve I65 is a piston type valve comprising a valve stem I66 having a plurality of spaced valve pistons formed integrally therewith to form valve chambers I61, I68 and I69. A compression spring I10 serves normally to hold the valve stem I66 in a left-hand end position so that fluid under pressure in the pipe 83 can not pass into the pipe I52. In this position of the valve I65 fluid may exhaust from the cylinder chamber I5I and s the pipe I52 into the valve chamber I69, through a central aperture I1I, into the valve chamber I61 and pass out through the pipe I62 and the throttle valve I63 into the reservoir 82. A solenoid S2 is provided which when energized serves to shift the valve stem I66 into a right-hand end position so that fluid under pressure in the pipe 83 may pass into the valve chamber I68 and through the pipe I52 into the cylinder chamber I5I so as to cause the piston I46 to move toward the left thereby rotating the swivel screw I35 so that a clockwise swivelling adjustment is imparted to the swivel table I4.

A pair of work gauging heads I and I8I are provided. These gauging heads are positioned to engage spaced workpieces 36 and 39 of the workpiece 23 or in the case of a wide wheel grinding operation, the gauge heads I80 and I8I are located to engage the workpiece adjacent the opposite ends thereof as illustrated in Fig. 7. These gauge heads may be any of the standard wellknown varieties. A gauge head has been illustrated in Fig. 6 comprising a frame I82 which supports a c-shaped head I83 having a pair of adjustably mounted contact screws I84 and I85. The frame I82 supports a slidably mounted plunger I86 the upper end of which engages a rock arm I81 pivotally supported on a stud I88. A compression spring I89 serves normally to exert a downward pressure on the plunger I86 to maintain the adjustable screw I in engagement with the workpiece 23. The rock arm I81 is provided with a contact element I90 which is arranged to swing in a clockwise direction as the workpiece is reduced in size to engage a contact element I9I which is fixedly supported and insulated from the frame I82.

Both of the gauge heads I80 and I8I are identical consequently only one of the gauge heads has been illustrated in Fig. 2. It is desirable that these gauge heads be inoperative until the workpiece is ground to approximately the desired and predetermined size. The gauge heads are connected in series with a normally open limit switch I having an actuating roller I96. A pivotally mounted feed stop pawl I91 is pivotally mounted on a stud I98 and arranged in the 7 path of an adjustable stop abutment I90 carried by the feed wheel 59. When the feed wheel 59 rotates in a counter-clockwise direction during an infeeding movement of the grinding wheel, just before the abutment I90 engages the upper end of the stop pawl I91, a earn 200 carried by the abutment I99 engages a roller I04 on the stop pawl and rocks the stop pawl I91 in a counter.

clockwise direction. A lever 20I which is fixedly mounted relative to the stop pawl I91 is similarly rocked in a GOUHtBIe-OIOQkWiSG direction so that an adjustable detent 202 on the end thereof engages the actuated roller I96 and closes the limit switch I05 to render the gauge heads I80 and I8I operative.

Closing of the contact elements I and IOI in the gauge head I00 serves. after the limit switch I95 has been closed to energize the solenoid SI thereby shifting the valve stem I50. toward the right so that fluid under pressure is passed through the pipe I40 to cause the piston I-ifi to move toward the right (Fig. 2). Similarly when the contact elements I90 and IQI of the gauge head I 0| are closed, the solenoid S2 is energized to shift the valve stem I66 toward the right so that fluid under pressure may pass through the pipe I52 into the valve chamber I5I to cause the piston I to move toward the left. If the. portions 36 and 39 of the workpiece 23 are ground to the desired and predetermined size at the same instant, both of the gauge heads I80 and I8I will be closed to energize both the solenoids SI and S2 so that fluid under pressure is simultaneously passed through the pipe I09 and I5I into cylinder chambers I and ISI respectively so that no motion will be imparted to the piston I43. If, however, the portion 30 is ground to size prior to the portion 39, the contacts I90 and IOI of the gauge head I30 will be closed to energize the solenoid SI so that fluid under pressure passes through the pipe I00 into the cylinder chamber I50 to move the piston I06 toward the right thereby rotating the swivel screw I35 to impart a counter-clocke wise swivelling movement to the swivel table I I. This swivelling adjustment of the table I4 continues until the portion 39. reaches size. Closing of the contacts I90 and IQI in the gauge head [8| serves. to energize the solenoid S2 thereby shifting the valve. stem I66. toward the right. so that fluid under pressure passes. through the pipe I52 into the cylinder chamber I51 thereby balancing the, pressure of opposite ends of the piston 46 to. stop further swivellin movement of. the swivel table I l.

At the same time the contacts :00 and MI of. the gauge head, I80 are closed, a relay switch CRI. is energized to open a. circuit. Similarly when the. contact elements I00 and IGI of the gauge. head I8I are closed, a relay CR2. is energized at. the same time the solenoid S2 is. energized. When both of the relays CRI and CR2 are energized thereby opening normall closed contactors. the solenoid S3 will be deenergized and the released compression of the spring 11 will return the valve stem 'iI toward the right into. the position illusmated in. Fig. 2 thereby reversing the flow of fluid t0 the feed cylinders I55 and I05so that the piston causes a rearward movement of the wheel slide 30. together with the grinding wheels 32., 3.3, 34 and35. At the same timethe piston I06 is moved toward the leftto rotate the feed screw 05. thereby resetting the feed screw into its initial position ready for the next. grinding operation.

A manually operablev control lever 205 is provided. for controlling. the stopping and. starting of the wheel feeding cycle. The control lever 205 is pivotally mounted on a stud 206 mounted on the front of the machine base I0. When it is desired to start a feeding cycle, the lever 205 (Fig. 2) is rocked in a counter-clockwise direction to close anormally open start switch 201. Similarly if the control lever 205 is rocked in a clockwise direction, it actuates a stop switch 208 to open the circuit at any time during a feeding cycle if it is desired to interrupt the cycle of operation.

The operation of the improved grinding machine will be readily apparent from the loregoing disclosure. Assuming all of the adjustments to have been previously made and a worke piece 23 is mounted in position between the work supporting centers 22 and 25, a grinding cycle may be initiated by rocking the control lever 205 in a counter-clockwise direction to close the starter switch 20?. Closing of the starter switch 20'! serves to energize the solenoid S3 to shift the feed control valve I0 toward the left (Fig. 2) to cause aforward rapid approaching movement of the grinding wheel slide 30. At the same time, the feed control valve I0 admits fluid under pressure to the cylinder I02 to start the piston I00 moving toward the right to cause a slow rotation of the feed screw 45. The movement of the piston 60 toward the left continues until the piston engages the left-hand end of the cylinder 05 after which continued movement of the piston I06 toward the right serves to produce a grinding feed. Closing of the start switch 20'! serves also to energize the normally open relay switch CR3 which sets up a holding circuit so that an instantaneous actuation of the starter switch 201 is sufficient to initiate a feeding cycle. The forward feeding movement of the grinding wheel slide continues until the cam 200 carried by the abutment I99 on the feed wheel 59 engages the roller I94 to close the normally open limit switch I90 thereby rendering the gauging heads I and I8I operative. The infeeding movement of the grinding wheel slide 30 continues until both of the portions 36 or 39 of the workpiece 23 have been reduced to a predetermined size. If a taper adjustment is required, the contact elements I00 and I9I of the gauge head I80 close indicating that the portion 30 is reduced to a predetermined size. The closing of the contacts I00 and I9i of the gauge head I80 serves to close a circuit to energize a relay switch CRI which opens the normally closed contactors thereon and at the same time energizes the solenoid SI to shift the valve stem I56 toward the right so that fluid under pressure may pass from the pipe 83 through the pipe I49 into the cylinder chamber I50 to cause the piston I46 to move toward the right. Movement of the piston I46 toward the right causes a rotation of the swive1 adjusting screw I35 to swivel the swivel table I4 in a counter-clockwise direction. Due to the swivelling of the swivel table I0, grinding will continue until the contacts I00 and I9I of the gauge head I8I close indicating that the swivel table has been ad justed to compensate for taper. Closing of the contacts I00 and I9! of the gauge head I8I serves to energize the relay switch CR2 to open the normally closed contactor thereon. At the same time closing of the contactors I00 and I ill of the gauge head I00 serves to energize the solenoid S3 to shift the valve I08 toward the right so that fluid may pass from the pipe. 83 through the pipe 52 into the cylinder chamber I5I thereby equalizing the pressure. in the cylinder chambers I50 and I5.I. to stop the movement of the piston I46 toward the. right.

When both of the relay-switches CRI and CR2 have been energized, a circuit is opened to deenergize the solenoid S3 thereby releasing the compression of the spring I1 so that the valve stem 1| moves toward the right (Fig. 2) so that fluid under pressure is passed into the cylinder chamber 8'! rapidly to return the piston 66 and the wheel slide 30 to a rearward or inoperative position. At the same time fluid under pressure is admitted to the cylinder chamber I20 to move the piston I06 toward the left (Fig. 2) to reset the slow feeding mechanism for the next grinding cycle.

If it is desired to compensate for taper on spaced portions on a workpiece or on a relatively long workpiece and to allow a further finish grinding operation after the swivel adjustment has been made, a normally open selector switch 209 is closed. The mechanisms operate in the same manner as above described except that opening of the limit switches CR! and CR2 will not deenergize the solenoid S3 due to the closing of the selector switch 209 which maintains the solenoid S3 energized. Grinding may then continue until the stop abutment I99 engages the upper surface of the feed pawl I91 thereby positively stopping the infeeding movement of the wheel slide 30. When the stop abutment I99 moves into engagement with the upper end of the feed pawl I91, the manually operable control lever 205 is shifted in a clockwise direction to open the stop switch 208 which breaks the circuit thereby returning the wheel slide and the grinding feed mechanism to the initial positions ready for the next cycle of operation.

The mechanism above described operates in an identical manner in grinding a relatively long workpiece such as shown in the modification illustrated in Fig. 7.

The grinding machine as above described shows the application of this invention for compensating for taper in grinding spaced portions on a single workpiece or in grinding a wide faced workpiece to a true cylindrical surface. This apparatus is equally applicable for taper grinding. The gauge heads I80 and i8! may be adjusted for a predetermined taper being ground after which the mechanism above described will function to produce the correct taper on the workpiece being ground.

It will thus be seen that there has been provided by this invention a grinding machine in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinally reciprocable table, a rotatable work support on said swivel table for supporting a cylindrical-type workpiece, a transversely movable grinding wheel slide, a feeding mechanism therefor, an automatically actuated taper compensating mechanism to swivel said swivel table, and a pair of gauges arranged to engage spaced portions on a workpiece being ground to actuate said com- 10 pensating mechanism to swivel the table so as to compensate for taper.

2. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinally reciprocable table, a rotatable work support thereon for supporting a cylindrical-type workpiece, a transversely movable grindingwheel slide, a feeding mechanism therefor, an automatically actuated taper compensating mechanism. to swivel said table, a pair of spaced independent gauges arranged toengage spaced portions on a workpiece being ground, and a control mechanism actuated by said gauges automatically to actuate said compensating mechanism to swivel the table so as to compensate for taper.

3. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinally reciprocable table, a rotatable work support thereon including a headstock and a footstock for supporting and rotating a cylindrical-type workpiece, a transversely movable grinding wheel slide, a feeding mechanism therefor, and an automatically actuated taper compensating mechanism including a nut and screw to swivel said swivel table, power operated means to rotate said screw,'a pair of spaced independent electric gauges to engage spaced portions on a workpiece being ground; and a control mechanism for said power means which is actuated'by said gauges automatically to swivel said table so as to compensate for taper.

4. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinally reciprocable table, a rotatable work support thereon including a headstock and a footstock for supporting and rotating a cylindrical-type workpiece, a transversely movable grinding wheel slide, a feeding mechanism therefor, and an automatically actuated taper compensating mechanism including a nut and screw to swivel said swivel table, a fluid motor to actuate said screw, a pair of spaced independent electric gauges arranged to engage spaced portions on a workpiece being ground, and a control mechanism for the fluid motor which is actuated by said gauges automatically to swivel said table so as to compensate for taper.

5. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinally reciprocable table, a rotatable work support thereon including a headstock and a footstock for supporting and rotating a cylindrical workpiece, a transversely movable grinding wheel slide, a feeding mechanism therefor including a rotatable feed wheel, a positive stop for limiting the infeeding movement of said slide, and an automatic taper compensating mechanism including a nut and screw to swivel said swivel table, a fluid motor to actuate said screw, a pair of spaced independent electric gauges to engage spaced portions on a workpiece being ground, means including a limit switch actuated by rotation of the feed wheel before the positive stop is reached to render said gauges operative, said gauges serving automatically to swivel the swivel table to compensate for taper, and a selector switch to facilitate continuing the grinding operation thereafter until the positive stop limits the forward feeding movement of the wheel slide.

6. In a cylindrical grinding machine having a base, a longitudinally reciprocable table thereon, a swivel table on said longitudinal table, a rotatable work support on said swivel table including a headstock and a rootstock for supporting and rotating a cylindrical workpiece, a transversely movable grinding wheel slide, a feeding mechanism therefor, and an automatically actuated taper compensating mechanism including a. nut and screw to swivel said swivel table, a fluid motor to actuate said screw, a pair of independent control valves independently to. control the admission to and exhaust of fluid from each side of said fluid motor, and a pair of spaced electric gauges each having normally open contacts arranged to engage spaced portions on a workpiece being ground; said gauges being arranged independently to control said control valves automatically to swivel the swivel table so as to compensate for taper.

7. In a cylindrical grinding machine having a base, a longitudinally reciprocabletable, a swivel table on said longitudinal table, a rotatable Work support thereon including a headstock and a footstock for supporting and rotating a cylindrical. workpiece, a transverselymovable grinding wheel slide, a feeding mechanism for controlling the transverse movement of the wheel slide to control the grinding operation, and an automatically actuated taper compensating mechanism including a nut and screw to swivel said swivel table, a fluid motor to rotate said screw, a pair of independent control valves independently to control the admission to and exhaust of fluid from each side of said motor, a pair of spaced normally inoperative electric gauges each having normally open contacts, said gauges being arranged to engage spaced portions on a workpiece "being ground, eachofsaidgaugesbeing arranged to control one'of said valves so as toswivel-the swivel table and to compensatefortaperon the workpiece being ground, and means including a limit switch actuated by and in timed relation with the feeding mechanism to render said gauges operative before the workpiece has been ground toapredeterminedsize to effect a taper compensation.

8. In a cylindrical grinding machine as claimed in claim 7; in combination with the parts and features thereinspecified in: which the feeding mechanism includes a piston andcylinder for causing a transverse feeding movement of the wheel slide; a solenoid-actuated control valve therefor, and means'including a'start switch to energize said solenoid to initiate a grinding cycle, said. gauges being arranged automatically to swivel the swivel table to compensate for taper and being arranged so that after bothof the gauges have operated to deenergize said solenoid to move the wheel slide to an inoperative position.

OIVA; E. HILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date- 1,970,000- Dunbar et a1 Aug. 14, 1934 2,151,669 Wood et al Mar. 21, 1939 2,247,228 Flygare June 24, 1941 

